Probably then, is it usual for some capacitors these days to go bad without bulging or leaking? The "elite" branded capacitors in there all looked ok visually but they were glued down hard so I didn't ESR test them.
The fault actually has nothing to do with the opto/feedback...you're talking about pulses in microseconds here, so optos won't react that quickly. It's just fundamental to any type of flyback converter, there's nothing wrong with flybacks for power supplies up to around the 50 watt mark they are perfectly fine (if not a tad noisy and inefficient compared to forward or LLC converters, but not a big deal)
The main issue is because they have tiny primary caps the transformer is wound to work at low mains voltage, it would probably work just fine from 110V AC with some flickering on the backlight.
The buzzing is normal, nothing you can do about it, probably due to the backlight PWM which is at 100Hz.
Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.
odd is the conector to the logic board as only 12 pins and i cant find where the standby power is..
fact is i do have a blinking red light and nothing else anyone saw one like this?
Attached Files
Last edited by Rictec; 04-29-2017, 07:03 PM.
Reason: add a picture
odd is the conector to the logic board as only 12 pins and i cant find where the standby power is..
fact is i do have a blinking red light and nothing else anyone saw one like this?
This looks like a toshiba set i worked on a while ago i had same blinking standy light it turned out too be a eeprom fault what make is the tv and what lcd panel is used in it
This looks like a toshiba set i worked on a while ago i had same blinking standy light it turned out too be a eeprom fault what make is the tv and what lcd panel is used in it
its a lousy Branded Electronia but everything inside is Vestel that file you posted there is what i got but i dont have any standby light only 12v on 12 pin of the connector to the logic board
there is any way i can put the files inside the flash without removing them?
the tv tries to read the usb pen cos it lights up but i dont think i have a firmware to put there
anyone have those files the file talks about so i can try them
thank you
Attached Files
Last edited by Rictec; 04-30-2017, 01:35 PM.
Reason: add a pictures
Hello to everyone! I'm working on a Telefunken L22F185D3D. Inside everything is made by Vestel, including this PSU. The television is dead with the only sign of life being the flashing red led.
I was confident it had to do with the 'famous' diodes but unfortunately this isn't the case. All the diodes in blue are fine (I've desoldered all of them from the board and tested them off circuit by a multimeter like it might be done if I've correctly understood). I've also tested the coils in red (fine too) and the fuse in yellow (fine, not that I expected anything different: should it have been shot, the TV had been completely dead, no blinking leds whatsoever apart from the fact that usually a bad fuse means a problem elsewhere, am I right?).
I've taken the photo online just to underline the components I'm talking about: should someone need a photo taken to my PSU itself, I'm free to make one.
I've visually checked all the caps: all of them seem absolutely fine, no bulged ones or else. My knowledge ends here unfortunately... I was used to some pins from where I could get peculiar voltages to check if the output given by the PSU was fine or not but this doesn't seem to be the case or, better said, it certainly is but it isn't so well documented on the board itself like it happens with other boards...
What I'm supposed to check now? Maybe the smaller diodes? Maybe the PSU is actually fine and the culprit is the motherboard (I fear this one)?
Thanks in advance to everyone for their advices and have a good day!
It's always best to have the original board top and bottom pictured. Sometimes people spot faults on the board.
Can you give the voltage on the pins of the black connector and the pin name.
Hi and first of all thanks for your prompt and kind replies! Right now I haven't still fitted the diodes back on the board so I can't take any voltage measurement but I'll do it ASAP, I hope in a couple of days or so.
What I would do even sooner is taking an actual photo of my board, both sides: Dick's advice is absolutely correct.
I thank you both for the advice about the schematic and giving me also a detail image from it. I apologize for not thinking about it by myself and I apologize again because I'm sure I'm going to make a super-dumb question.
If I read that schematic well (probably not or at least not completely), from that connector I could take the measurements for:
12V between 13/14 and 2
5V between 9 and 2
24V between 15 and 2
Am I completely wrong or am I missing something? I miss 3.3V for example... Please forgive me: I've told you this was going to be a super-dumb question!
you can use the metal tv chassis as a ground then just use the red probe to test the voltages test pins 3/5/7/9/13/14/15
i think these sets suffer from eeprom issues so like you say maybe a main board issue
Last edited by vinceroger69; 04-27-2018, 12:04 PM.
Yes, I've read about the eeprom issues and I fear it is my case too. Should it be, then I'm lost because I don't think a recovery procedure made through USB by an end-user does exist. Apart from a procedure which may exist, a faulty eeprom remains that and it needs to be replaced before so I'm lost anyway.
I thank you for your confirmation on how to take the measures. Just to learn, given that pin 2 goes to ground, was using it correct too? I assume yes but certainly touching the chassis is handier and this probably is the reason for your advice. Thanks for everything!
yes you can use any ground on that connector i just find it easier myself to clip black probe onto metal tv chassis we all test things in different ways though.sometimes you can get lucky and heat or freeze the eeprom if this then gets the set powered on you can sometimes read the eeprom data save it then write it back too a new ic
Am I completely wrong or am I missing something? I miss 3.3V for example... Please forgive me: I've told you this was going to be a super-dumb question!
What about the voltage between pins 3 to 2, pins 5 and 2, pins 7 and 2
A shot in the dark here but are all the screws that hold the boards down tight? As I've seen some youtube videos where the chassis is used as a return path between board sections and the heating and cooling cycles and movement flexing can cause these screws to become loose which causes bad connections.
Hello to everyone and first of all please excuse me for not coming back before.
First of all, here are the actual photos for my PSU:
the third one being a detail of a thermistor with a black mark on it: it doesn't seem a burning sign though, just some kind of glue.
The readings are very strange, here they are:
I know that according to the schematics for the board I'm supposed not to be getting any voltage reading on pin 11 but I've double checked. Also, pin 11 isn't NC as in the schematics but connected to a resistor.
Another difference is that pin 14 and 18 are bridged.
For what concernes the screws, yes I had noticed they were somewhat loose.
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